[postgis-users] Determining clusters of points

[Sébastien Lorion]

Hello Kevin,

I am still testing/trying stuff .. One strange thing I saw is that if I set
the range to 40 instead of 80, then there are more clusters than there
should be, but at 50 it is ok. Using the buffer/merge method, it works
correctly. I did not investigate further into that.

Sébastien

On Wed, Dec 8, 2010 at 11:24, Kevin Neufeld <kneufeld.ca at gmail.com> wrote:

> On 12/8/2010 7:38 AM, Sébastien Lorion wrote:
>
>>
>> The points are not static, they will potentially be in a different
>> position each time the query is run.
>>
>
> Ah, I was going to ask about that.  It might be possible to create a
> recursive query to maintain a very large point table as new records are
> added (add them to existing clusters and / or merge clusters), but according
> to my initial findings, there is no way a recursive query approach is going
> to be able to scale well enough for your million points, esp. if you need to
> be able to run such a query every 30 min.  But I'd be curious to hear what
> your findings are as well.
>
> -- Kevin
>
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